Re: [PATCH v5 06/22] coco/tdx-host: Expose P-SEAMLDR information via sysfs

From: Xiaoyao Li

Date: Wed Mar 18 2026 - 04:24:30 EST


On 3/18/2026 2:54 PM, Chao Gao wrote:
+
+What: /sys/devices/faux/tdx_host/seamldr/version
+Contact: linux-coco@xxxxxxxxxxxxxxx
+Description: (RO) Report the version of the loaded SEAM loader. The SEAM
+ loader version is formatted as x.y.z, where "x" is the major
+ version, "y" is the minor version and "z" is the update version.
+ Versions are used for bug reporting and compatibility checks.
+
+What: /sys/devices/faux/tdx_host/seamldr/num_remaining_updates
+Contact: linux-coco@xxxxxxxxxxxxxxx
+Description: (RO) Report the number of remaining updates. TDX maintains a
+ log about each TDX module that has been loaded. This log has
+ a finite size, which limits the number of TDX module updates
+ that can be performed.
+
+ After each successful update, the number reduces by one. Once it
+ reaches zero, further updates will fail until next reboot. The
+ number is always zero if the P-SEAMLDR doesn't support updates.
+
+ See Intel® Trust Domain Extensions - SEAM Loader (SEAMLDR)
+ Interface Specification, Revision 343755-003, Chapter 3.3
+ "SEAMLDR_INFO" and Chapter 4.2 "SEAMLDR.INSTALL" for more
+ information.

Do you think revision and chapter numbers useful here?

I think it's nice-to-have. Without specific references, people would need to
read the entire 26-page spec. But I can drop them if they make it too verbose.

I have some concerns about the "revision". The good thing is that it can tell what the attribute was built against while the bad thing is that it might not be easy for people to find an old revision years later.